1. Field of the Invention
The present invention relates to copper alloys having improved properties and more particularly, the invention relates to spray cast alloys having a uniformly dispersed second phase and a solid state precipitate.
2. Background Information
Copper based alloys are widely used for electronic, electrical, and thermal applications. Electrical connectors and leadframes are usually formed from copper alloys to exploit the high electrical conductivity inherent in the alloys. Heat sinks, heat exchanger coils, and cooling fins are also manufactured from copper based alloys to take advantage of the excellent thermal conductivity of the alloys.
The copper based alloys are often cold worked following casting to increase the strength of the alloy. When exposed to elevated temperatures, the alloys recrystallize. Recrystallization is accompanied by a loss of structural strength. This phenomenon is often expressed in terms of softening resistance. Softening resistance is a measure of the ability of an alloy to resist deformation when exposed to elevated temperatures. It is desirable to fashion a copper based alloy having high thermal conductivity and high electrical conductivity which also resists softening at elevated temperatures.
A method of manufacturing such copper alloys having improved softening resistance is disclosed in co-pending U.S. application Ser. No. 385,034, filed Jul. 26, 1989. According to that method, spray casting is used to produce an alloy having a second phase of dispersoid uniformly dispersed throughout a matrix of a copper based alloy. It has been found that alloys produced in accordance with this application also have improved stress relaxation. Stress relaxation is defined as a loss of stress while at a constant strain.
In addition to improved softening resistance and stress relaxation, it is also desirable that alloys for certain electrical and electronic properties have good mechanical properties. In certain applications, the alloys are subjected to applications in which mechanical failure may be a problem. Accordingly, it is desirable that such alloys have good tensile strength, yield strength, and good bending properties.